**1. Introduction**

Medicinal plants, which are undervalued, have an important place in modern medicine owing to the multitude of active principles that nature provided through millions of years of evolution. These numerous plant chemicals or phytochemicals possess far reaching, biologically active, beneficial effects and provide protection to the plants from insects, bacteria, virus and other predators. These phytochemicals either alone or in combination affect multiple pathways simultaneously to produce the desired pharmacological effect. Many medicinal plants or herbs are revered by the ancient medical traditions (Chinese medicine, Ayurveda, Native Americans, etc.) due to their healing benefits and about 40% of modern medicines are derived from plants [1–3]. The development of antibacterial and anti-infectious agents is a major focus in modern medical research. Plant-based antiviral formulations have been studied for their therapeutic potential in the managemen<sup>t</sup> of various viral diseases including influenza, human immunodeficiency virus (HIV), herpes simplex virus (HSV), hepatitis, and coxsackievirus infections [4–7].

One particular plant that has garnered a lot of attention in lieu of the COVID-19 epidemic is Artemisia which is one of the largest and most widely distributed genera of the family Astraceae (Compositae) [6,8]. Artemisia is a varied genus consisting of more than 500 diverse species and is found in the temperate zones of Europe, Asia and North America [9–11]. Evidence-based in vitro and in vivo studies on several species of

**Citation:** Kshirsagar, S.G.; Rao, R.V.Antiviral and Immunomodulation Effects of Artemisia. *Medicina* **2021**, *57*, 217. https://doi.org/10.3390/ medicina57030217

Academic Editor: Robert H. Schneider

Received: 23 January 2021 Accepted: 25 February 2021 Published: 27 February 2021

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Artemisia resulted in the identification of numerous phytochemicals with varied pharmacological activities, including terpenoids, flavonoids, coumarins, caffeoylquinic acids and sterols [12,13]. The first clinical trial of Artemisia extract in human patients with malaria was conducted in August 1972. Following that trial, the active compound in the Artemisia extract was isolated and identified as artemisinin. Several derivatives or synthetic compounds with key structures similar to artemisinin have now been developed including artesunate and piperaquine from *A. annua* and piperitone and trans-ethyl cinnamate from *A. judaica* that have potent antiviral and anti-inflammatory activities [9,14–16]. A combination of artemisinin and its derivatives (ARTs) is now recommended by the World Health Organization (WHO) for the treatment of malaria.
